I have been studying the 1394imaging sight for DMK cameras.
The DMK that a well known Adelaide astronomer is using=DMK21AF04 mono. Which has similar specifications and sensitivity to the DFK21AF04 which as I understand can take both Mono and Colour Avis. The DFK is $20.00 US cheaper than the mono. Both cameras capture at the same fps and are 0.5 lux @ 1/30sec and 20dB.
To me the DFK can capture in both colour and mono. So can be used with filters or without filters. It could also capture at 30 fps without compression which toucams and neximage cannot do.
Can someone who knows more than I explain why the DFK is not used for imaging planets, because I cannot find a reason when looking at the specifications.
That's what I mean Lester.. if it's a colour camera then it can't capture in mono. It's probably just capturing in black and white, like the ToUcam can do.
It's not a true mono camera though.. At least that's my understanding. So it won't be capturing at full resolution.
I could be wrong though. It would be good if it could do - because you can start out capturing colour before diving into RGB imaging.
A colour camera can be used for planetary imaging such as the ToUcam. As for sensitivity, the monochrome camera is more sensitive, but if the monochrome camera is used in combination with Red Green Blue filters then the camera come back to about the same level of sensitivity as the colour camera. The main advantage of monochrome camera plus RGB filters is that you get a true 640x480 resolution in each colour.
I should have read your first post more closely. When we are talking about sensitivity the mono and colour camera have the same Lx value. I what I should have said, and I hope I get this right, is spectral response. If you take your standard colour camera such as the TuCam, the CCD has a RGB filter (Bayer Filter) incorporated into the chip. This mean that each pixel of a 640X480 chip will have its on individual colour filter. It works out that 1/3 of the chip is red, 1/3 is green and 1/3 is blue.
While a colour camera is great you are losing information. I have a USB 2 Lumenera colour camera and while it takes great images of the planets there are limitations. From what I have seen of Damian Peaches work with the monochrome version of the Lumenera there is a definite advantage it using RGB filters (refer back to my first post)
Bye for now got go and watch CSI
Anthony
Last edited by anthony2302749; 29-05-2006 at 03:49 PM.
The mono DMK is only US$490, so you could do imaging of the moon at full resolution, and get coloured filters later..
Or, get a cheaper filterwheel + filters for $200-$500. I don't know that it's absolutely necessary to get the astronomiks branded colour filters at $200 or more each. I guess you'd need to do some experiments to determine if there's any reduction in quality by using "lesser branded" colour filters.
comparing recent paul haese, a little older bird one with their dmk b/w and fireware and my older toucam one in very similiar conditions showed the differences up I believe.
There is a 30 fps uncompressed colour camera due for release from ambermile I hope very soon, but after that it is really a step up to the b/w sensor with colour filters and maybe a L filter as well
I have asked Damian P and Bird about Luminescence ie a 4th filter in the filter wheel. Bird believes it is an unneccessary step and Damien agrees with Jupiter so high in the sky.
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Hi David,
>>>What does the luminescence give you and can it be used if you have
>>>not captured in L,R,G,B separately?
This gives you a superior signal/noise image than using straight RGB. Its been long practiced in the Deep Sky world for many years. For example if you took say 40sec in each filter, you could combine (average) the three to create a smooth luminance image. You then then replace the luminance of the normal RGB in photoshop with your new smoother luminance which would hopefully create a superior overall image. Hope that makes some sense :-).
Best Wishes
Damian
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>>>So this can only really be done via a fourth filter in the filter
>>>wheel
and not some software tweeks from a single pass colour avi capture ie a toucam with a colour ccd chip?
It can be done with a colour camera working in mono mode with filters but given the high altitude of Jupiter for you its probably more hassle than its worth. Colour cameras work great when the Planets are high in the sky.
Damian
Some people create an artifical luminance layer by combing the R&G channels.
DP are you sure about 30fps uncompressed? From what I read of the ambermile cameras, they're not going to be USB2, and therefore not 30fps uncompressed.
Interesting comments here. I was looking into one of these cameras too.
So what I deduce from all this is: it would be a step up from the toucam, but it will still eat the mono/RGB filter cameras dust.
A colour industrial camera such as the Lumerena LU075C and DKF will defiantly out perform any commercally avaliable webcam due to high-speed USB 2.0 or Firewire which can provide up to 60fps uncompressed data.
The Lumerena and DMF mono plus RGB filter will, IMO out perform their colour versions. This knowledge comes through experience, as I have mentioned, I own the colour version of the Lumerena and the one thing that I have notice is when splitting a BMP into Red, Green and Blue channels the blue channels looks to contain the most noise. Something you do not see when imaging with a monochrome camera and blue filter (I refer you back to the work done by Damian Peach and Paolo Lazzarotti.
Bye again, got to get back to work, will finish this discusion later
I am always looking for the easy way out and if the DFK 21AF04 is going to be 2-3 x better than the neximage and I don't have to hassle with filters and refocusing inbetween some of the filters then I think its worth a try.
I hear what you are saying Anthony, that the mono cameras DMK or Lumenera are the best for giving the most detail and the sharpest image, but it would be a lot more work too. Its a pity there are not any planetary images taken with the colour DFK or Lumenera on the web. Have you taken any planetary shots with your colour Lumenera Anthony?
There are plenty of planetary images taken with the colour Lumenera. Wes Higgins (one of the best lunar/planetary astrophotographers in the world) posted here on CloudyNights.
Anthony has posted some nice ones here too, just search under the solar system forum for threads started by Anthony.
I haven't seen any taken with the colour DFK, though. But I imagine it will do a good job still, still much better than the ToUcam. Just make sure you have the appropriate ports in your laptop for plugging it in!
The colour DFK is a much better (ie: cheaper) option than the colour LU.
I am leaning towards the colour version. I dont see the need to go to the extra expense of buying filters and wheels just yet, but this is a very personal opinion. Never know what the future hold though. Gotta get myself some decent optics yet.
